A hard disk is a main storage medium of a computer, and a solid state disk (SSD) is relatively common among hard disks. An SSD is a hard disk made of a solid state electronic storage chip array. The SSD stores data mainly using a flash chip as a storage medium. Currently, a relatively common flash chip is a negative and (NAND) flash. In a currently common NAND flash, each chip enable (CE) of the NAND flash is corresponding to 8192 blocks, and each block includes 128 pages, where a page is a minimum unit used when the NAND flash performs a read or write data operation, and a size of each page is generally 4096 (4K) byte (B). However, a minimum unit used when a host performs a read or write data operation on a hard disk is one sector, and a size of each sector is generally 512 B. It may be learned from the above that the minimum unit used when a host performs a read or write operation is inconsistent with the minimum unit used when a NAND flash performs a read or write data operation. When a host performs a write operation, if data that the host writes to a NAND flash is less than one page, the data can be successfully written to the NAND flash using a pre-padding solution.
It is known to all that a hard disk is vulnerable to a fault, and an uncorrectable error correcting code error (UNC) is one of most common faults. Currently, a redundant array of independent disks mechanism is usually used to resolve a UNC problem. When a UNC occurs in one of hard disks, data may be re-written, by reading information of another disk, to a location in which the UNC occurs, to achieve a repair objective. However, in a hard disk in which a NAND flash is used as a storage medium, a minimum unit used when a host performs a read or write data operation is one sector (for example, one sector is 512 B), while a minimum write unit of the NAND flash is one page (for example, one page is 4 KB). Therefore, a pre-padding solution needs to be used such that data can be successfully re-written to a location in which the UNC occurs, to perform repair. If the UNC occurs in an entire page, when the host performs repair in a unit of sector, and when the hard disk receives a write instruction from the host for a sector, a page in which the sector is located needs to be read into a random access memory (RAM). However, because the UNC occurs in the entire page, reading may fail. In this way, the hard disk may quit this write operation, and replies with writing success to the host. In this case, the host performs a read operation again on the sector, to determine whether a repair operation performed by the host on the sector is successful. The hard disk actually has not successfully write data to the sector. Therefore, the host fails to read and determines that a disk in which the sector is located is faulty (actually, the disk can still be used). Finally, the disk is removed, which causes redundant array of independent disks (RAID) degradation and affects system reliability.